Wheel hub drive unit with a fluid circuit

Abstract

The invention relates to a wheel hub drive device (200) for a motor vehicle, with a fluid circuit (100), in particular a cooling and / or lubrication circuit, with a drive axle (10) on which at least a first wheel hub drive (14) and at least a second wheel hub drive (34) are arranged, wherein at least a first stator (18) of a first electric machine (16) of the first wheel hub drive (14) and a second stator (38) of a second electric machine (36) of the second wheel hub drive (34) and respective transmission elements (22, 24, 26, 42, 44, 46) of first and second transmission devices (20, 40) of the first and second wheel hub drives (14, 34) are fluidically connected to the fluid circuit (100).The fluid circuit (100) has at least one double-flow pump (50), with a first flow (52) which draws fluid from the first wheel hub drive (14) and delivers it to the second stator (38) and with a second flow (62) which draws fluid from the second wheel hub drive (34) and delivers it to the first stator (18).

Description

[0001] The invention relates to a wheel hub drive device for a motor vehicle, with a fluid circuit, in particular a cooling and / or lubrication circuit.

[0002] In an electric wheel hub drive with high power density, active lubrication and cooling of the electric motor and the transmission components are necessary due to the temperatures that occur. The cooling and lubricating oil supplied to the individual components is cooled after passing through these components and returned to an oil reservoir to complete an oil circuit.

[0003] One object of the invention is to create an improved wheel hub drive device for a motor vehicle, with a fluid circuit, in particular a cooling and / or lubrication circuit.

[0004] The aforementioned problem is solved using the features of an independent claim.

[0005] Favorable embodiments and advantages of the invention will become apparent from the further claims, the description and the drawing.

[0006] According to a further aspect of the invention, a wheel hub drive device for a motor vehicle, comprising a fluid circuit, in particular a cooling and / or lubrication circuit, is proposed, with a drive axle on which at least a first wheel hub drive for a first wheel and at least a second wheel hub drive for a second wheel are arranged, wherein at least a first stator of a first electric machine of the first wheel hub drive and a second stator of a second electric machine of the second wheel hub drive and respective transmission elements of the first and second transmission units of the first and second wheel hub drives are fluidically connected to the fluid circuit. In particular, the first electric machine and the first transmission unit are arranged essentially in the first wheel and the second electric machine and the second transmission unit are arranged essentially in the second wheel.The fluid circuit includes at least one dual-flow pump, with a first flow that draws fluid from the first wheel hub drive and delivers it to the second stator, and a second flow that draws fluid from the second wheel hub drive and delivers it to the first stator. In particular, the dual-flow pump is located within the vehicle.

[0007] The fluid used in the drive device according to the invention can, in particular, be an oil that serves to cool and lubricate the electric machines and the gear elements of the transmission devices, especially to cool the stators of the electric machines and to lubricate the gear elements of the transmission devices. Cooling of the rotors of the electric machines can, in particular, be achieved by means of internal cooling channels in the respective rotor shaft, through which the oil then flows over the respective rotor disk(s). The cooling circuit system can thus alternatively or additionally be a lubrication circuit, since, in particular, the gear elements of the transmission devices are lubricated by the fluid. The fluid can therefore be described as a cooling and / or lubricating oil.

[0008] The fluid for both wheel hub drives is supplied by a shared pump. This pump has a dual-stage design, allowing both fluid circuits to be supplied simultaneously with just one motor and one control unit.

[0009] The first flow of the dual-flow pump serves to supply fluid from the first wheel hub drive to the second stator. The second flow of the dual-flow pump serves to supply fluid from the second wheel hub drive to the first stator. Thus, according to the invention, a first fluid sub-circuit, i.e., a fluid circuit by which the first wheel hub drive can be supplied with fluid, and a second fluid sub-circuit, i.e., a fluid circuit by which the second wheel hub drive can be supplied with fluid, are reciprocally combined.

[0010] By reciprocally combining the fluid sub-circuits, the fluid, and thus the wheel hub assembly according to the invention, and thus the first wheel hub drive and the second wheel hub drive, can advantageously be cooled with only one heat exchanger, since the fluid is pumped from one of the two pump stages into the opposite unit and passes through the fluid cooler, which is located only on one side, until it has completely passed through.

[0011] A further advantage is that by reciprocally combining the fluid sub-circuits of the two wheel hub drives, it is possible to use only one filter to filter both sides, since the fluid is pumped from one of the two pump stages into the opposite unit and passes through the filter, which is only located on one side, until it has completely passed through.

[0012] The installation space requirements, costs and weight of the proposed wheel hub drive unit can thus be advantageously reduced compared to conventional units.

[0013] According to an advantageous embodiment of the wheel hub drive device, a pressure filter can be arranged between the first flood and the second stator or between the second flood and the first stator. The pressure filter can advantageously filter the fluid sub-circuits for both wheel hub drives, since the fluid sub-circuits are reciprocally combined via the dual-flow pump.

[0014] According to an advantageous embodiment of the wheel hub drive unit, a wall extending circumferentially to each of the two drive units can be arranged in the respective base area of ​​the first and second drive units, in which an oil sump forms. The wall is connected, in particular in a substantially fluid-tight manner, to the respective wheel hub drive housing on one axial side of the wheel, which faces the vehicle. On another axial side, a section between the wall and the wheel hub drive housing is open to allow fluid ingress.

[0015] According to an advantageous embodiment of the wheel hub drive device, a cooling device, in particular a heat exchanger, can be arranged between the second fluid circuit and the first stator or between the first fluid circuit and the second stator to cool the fluid. By reciprocally combining the fluid circuits, the fluid can advantageously be cooled with only one cooling device.

[0016] According to an advantageous embodiment of the wheel hub drive device, the first and second floods can share a common electric drive motor and a common control system. This allows the proposed wheel hub drive device to be implemented cost-effectively.

[0017] According to an advantageous embodiment of the wheel hub drive device, the first stator can have a first stator return line for the fluid, which is hydraulically coupled to a first supply line of the fluid into the first reservoir, and the second stator can have a second stator return line for the fluid, which is hydraulically coupled to a second supply line of the fluid into the second reservoir. In this way, the fluid circuits of the two wheel hub drives can advantageously be combined reciprocally via the common dual-flow pump.

[0018] According to an advantageous embodiment of the wheel hub drive device, a connection for the respective supply line to the respective pump's fluid is arranged radially outside the respective wall and within a respective wheel hub drive housing area, which is axially covered by the respective wall. Advantageously, the provision of the respective wall prevents the pump from drawing in air, particularly during cornering.

[0019] According to an advantageous embodiment of the wheel hub drive device, the stator return lines can each be hydraulically connected via throttle elements to planets, support bearings, shaft-rotor bearings of the respective transmission devices.

[0020] This allows the fluid flow for cooling and / or lubrication to be advantageously divided between the transmission components and the respective oil sump via the throttling elements. The aim is to direct only relatively small quantities of fluid to the transmission components, with the majority of the cooling and / or lubricating fluid flowing directly back into the respective oil sump.

[0021] Further advantages will become apparent from the following description of the drawing. The drawing illustrates an embodiment of the invention. The drawing, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0022] This shows: Fig. 1 a system overview of a wheel hub drive device for a motor vehicle, with a fluid circuit, in particular a cooling and / or lubrication circuit, according to an embodiment of the invention.

[0023] In the figure, identical or similar components are numbered with the same reference symbols. The figure merely shows an example and is not to be understood as limiting.

[0024] Fig. Figure 1 shows a system overview of a wheel hub drive device 200 for a motor vehicle, with a fluid circuit 100, in particular a cooling and / or lubrication circuit, according to an embodiment of the invention.

[0025] The wheel hub drive device 200 has a drive axle 10 on which at least one first wheel hub drive 14 for a first wheel 12 (schematically shown with a wheel rim 13) and at least one second wheel hub drive 34 for a second wheel 32 (schematically shown with a wheel rim 33) are arranged.

[0026] A first stator 18 of a first electric machine 16 of the first wheel hub drive 14 and a second stator 38 of a second electric machine 36 of the second wheel hub drive 34 and respective gear elements 22, 24, 26, 42, 44, 46 of the first and second gear units 20, 40 of the first and second wheel hub drives 14, 34 are fluidically connected to the fluid circuit 100.

[0027] The fluid circuit 100 has a double-flow pump 50 with a first flow 52, ​​which draws fluid from the first wheel hub drive 14 and delivers it to the second stator 38, and with a second flow 62, which draws fluid from the second wheel hub drive 34 and delivers it to the first stator 18.

[0028] The first flood 52 and the second flood 62 can advantageously have a common electric drive motor and a common control system.

[0029] A pressure filter 72 is arranged between the first flood 52 and the second stator 38, i.e., upstream of the first flood 52 of the twin-flow pump 50. The filter 72 is hydraulically connected to the second stator 38 via a stator supply line 68.

[0030] Alternatively, the filter 72 can also be arranged between the second flood 62 and the first stator 18.

[0031] A cooling device 74, in particular a heat exchanger, is arranged between the second flood 62 and the first stator 18, i.e., upstream of the second flood 62 of the twin-float pump 50, for cooling the fluid. The cooling device 74 is hydraulically connected to the first stator 18 via a stator supply line 58.

[0032] Alternatively, the cooling device 74 can also be arranged between the first flood 52 and the second stator 38.

[0033] In a respective base area of ​​the first and second gear units 20, 40, a circumferentially extending wall 29, 49 (not shown) can be arranged. An oil sump 28, 48 is formed in each base area.

[0034] The first stator 18 has a first stator return line 56 for the fluid, which is hydraulically coupled to a first supply line 55 of the fluid into the first flood 52.

[0035] The second stator 38 in turn has a second stator return line 66 for the fluid, which is hydraulically coupled to a second supply line 65 of the fluid into the second flood 62.

[0036] The first and second return lines 56, 66 are each hydraulically connected via throttle elements 23, 25, 27, 43, 45, 47 to planets 22, 42, support bearings 24, 44, shaft-rotor bearings 26, 46 of the respective transmission units 20, 40.

[0037] The individual components of the fluid circuit 100, such as pump 50, filter 72, cooling device 74, are advantageously arranged in the vehicle chassis 90.

[0038] The wheel hub drive housings 15, 35 of the wheel hub drives 14, 34 are each connected via a closed vent line 92, 94. The vent lines 92, 94 are connected to a further vent line 96, which is open to the outside. Reference symbol list 10 drive axle 12 first wheel 13 wheel rim 14 first wheel hub drive 15 first wheel hub drive housing 16 first electric machine 18 first stator 20 first gearbox 22 planets 23 Throttle element 24 support bearings 25 Throttle element 26 shaft rotor bearings 27 Throttle element 28 first oil sump 29 first wall 32 second wheel 33 wheel rim 34 second wheel hub drive 35 second wheel hub drive housing 36 second electric machine 38 second stator 40 second gearbox 42 planets 43 Throttle element 44 support bearings 45 Throttle element 46 Shaft-Rotor bearing 47 Throttle element 48 second oil sump 49 second wall 50 pump 52 first flood 54 first connection 55 first feed line 56 first stator feedback line 58 first stator feed line 62 second flood 64 second connection 65 second feed line 66 second stator feedback line 68 second stator feed line 72 pressure filters 74 Cooling unit 90 vehicle chassis 92 Vent line 94 Vent line 96 Vent line 100 Fluid circuit 200 wheel hub drive unit

Claims

Wheel hub drive device (200) for a motor vehicle, comprising a fluid circuit (100), in particular a cooling and / or lubrication circuit, with a drive axle (10) on which at least a first wheel hub drive (14) for a first wheel (12) and at least a second wheel hub drive (34) for a second wheel (32) are arranged, wherein at least a first stator (18) of a first electric machine (16) of the first wheel hub drive (14) and a second stator (38) of a second electric machine (36) of the second wheel hub drive (34) and respective transmission elements (22, 24, 26, 42, 44, 46) of the first and second transmission devices (20, 40) of the first and second wheel hub drives (14, 34) are fluidically connected to the fluid circuit (100), wherein the fluid circuit (100) comprises at least one dual-flow pump (50), with a first flow (52) which Fluid is drawn from the first wheel hub drive (14) and conveyed into the second stator (38) and mixed with a second flood (62),which draws fluid from the second wheel hub drive (34) and delivers it to the first stator (18). Wheel hub drive device according to claim 1, characterized in that a pressure filter (72) is arranged between the first flood (52) and the second stator (38) or between the second flood (62) and the first stator (18). Wheel hub drive device according to claim 1 or 2, characterized in that a respective wall (29, 49) extending in a circumferential direction is arranged in a respective bottom area of ​​the first and second transmission devices (20, 40). Wheel hub drive device according to one of the preceding claims, characterized in that a cooling device (74) for cooling the fluid is arranged between the second flood (62) and the first stator (18) or between the first flood (52) and the second stator (38). Wheel hub drive device according to one of the preceding claims, characterized in that the first flood (52) and the second flood (62) have a common electric drive motor and a common control. Wheel hub drive device according to one of the preceding claims, characterized in that the first stator (18) has a first stator return line (56) for the fluid, which is hydraulically coupled to a first supply line (55) for the fluid into the first flood (52), and wherein the second stator (38) has a second stator return line (66) for the fluid, which is hydraulically coupled to a second supply line (65) for the fluid into the second flood (62). Wheel hub drive device according to claims 3 and 6, characterized in that the respective wall (29, 49) axially covers a respective connection (54, 64) of the respective supply line (55, 65) arranged in a respective wheel hub drive housing (15, 35). Wheel hub drive device according to claim 6, characterized in that the stator return lines (56, 66) are each hydraulically connected via throttle elements (23, 25, 27, 43, 45, 47) to planets (22, 42), support bearings (24, 44), shaft-rotor bearings (26, 46) of the respective transmission devices (20, 40).

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